The present invention relates in general to an improved system for dispensing controlled amounts of flowable material from within sealed flexible-walled containers, and in particular, to devices which press-pump materials having wide ranges of viscosities, temperatures, and particulate contents from flexible-walled containers.
The restaurant and consumer products industries are making increased use of flexible bags to contain food products. These bags are easy to handle and require less storage and shipping space. The flexible bags can be easily loaded into dispensers for dispensation of the food product, thereby reducing handling of the food product.
Flexible-walled bottles have long been used to dispense fluids by squeezing. Such bottles have been usually made with resilient walls which tend to restore to their original shape after removal of deforming forces. As the ratio of inside air to liquid increases with bottle use, difficulties are encountered in attempting to completely empty the bottle in a timely manner. Solutions to these problems have included placement of the fluid in an inner bag which is sealed within a squeeze bottle. Examples of such structures have been disclosed by Streck in U.S. Pat. No. 4,865,224 and Uhlig in U.S. Pat. No. 4,098,434.
Although the above solutions decreased the time required to empty the squeeze bottle, new problems associated with premature bag collapse and with potential exit orifice blockage arose. Semi-rigid internal bag cartridges which lessen these problems and various supporting structures placed inside the bag are known, such as the apparatus disclosed in U.S. Pat. No. 5,156,300 issued to Spahni et al. Combinations of such internal bag elements with dispensing means are also available. For example, in U.S. Pat. No. 4,138,036 to Bond a helical coil bag insert is coupled with a dispensing spout supported in the neck opening of a rigid external structure.
In addition, other combination devices have mated a protected dispensing orifice with a bag cutting and sealing means. An example of this approach is shown by Knorr in U.S. Pat. No. 5,127,550, wherein a first member having a throughbore therein is used in conjunction with a cutting means to seal adjacent portions of a bag wall together while piercing the bag wall for fluid release through the narrow passages cut therein.
Some prior art enfitments which are designed to penetrate a flexible bag protrude into the bag. The protruding portion of the enfitment interferes with piston or bag compression types of pumping. Also, the protruding device traps product that cannot be dispensed, thus, increasing waste of undispensed flowable material. These problems are increased when the food products include varied viscosity items, such as condiments, and when it is desirable to perform such tasks automatically.
The protruding enfitment device also interferes with a piston or bag compression type of pump for pumping the material from the bag. Further, such enfitment devices are often difficult to attach to the bag. These problems become worse when the bag contains material, such as food products, of various viscosity, such as condiments, and when it is desirable to perform such tasks automatically. In the restaurant industry, for instance, existing devices have been mostly useful in manual dispensing of condiments by customers.
In the area of rapid food preparation, especially in quick-service restaurants, a need exists to dispense controlled portions of a broad spectrum of material having uneven flow characteristics. Such materials include food products with variable viscosities, emulsions, colloidal suspensions which can coagulate or settle out with time, as well as semi-solid mixtures, such as relish, beans, meat, sour cream, cheese sauces, ketchup, or mustard. These materials must be moved or pumped in a manner in which the flowable material or product maintains its piece integrity. As an example, emulsions or suspensions must not be overworked to cause a shearing action or breaking of the emulsion.
Further difficulties arise in obtaining repeatable dispensations of a controlled amount of flowable material, especially when the temperature and viscosity of the flowable material varies over a wide range. The portion or amount of ingredient that is pumped from a flexible-walled container is usually dependent on one or more of the following: the amount of pressure, duration of pressure application, pressure-sensitive valves, exit hole size and product viscosity. For instance, if the time that the pressure is applied to the container is held constant, then the ingredient portion being dispensed will become smaller as the residual ingredient left in the bag is reduced.
Current dispensation of food products from flexible bags is achieved by transferring the food product into mechanical handheld dispensing devices or through the use of enfitments. Enfitments are attached to the bag and used to interface with a dispense hose or nozzle. Such enfitments can be either placed on the bag before loading within the device or attached within the handheld device. Each method, however, requires either additional labor to attach the enfitment to the bag or takes up space within the mechanical handheld device. In addition, manual attachment of the enfitment to the bag increases handling of the food ingredients and creates undesirable food handling risks.
The present invention provides a system for dispensing controlled amounts of flowable material which is stored in a flexible-walled container. The system of the present invention includes a second container configured to hold a first flexible-walled container, a piston, and an actuator connected to the piston to drive the piston along a stroke axis through a preset travel range. The system can be constructed in a modular manner to allow multiple dispensing systems to be placed in a space efficient manner in-line with varying sizes of storage capacities.
A flexible bag or other flexible-walled container containing flowable food product is positionable within the second container. The cross-sectional shape of the second container, as taken generally normal to the stroke axis of the system, is complementary to the cross-sectional shape of the first container.
The present invention further provides an enfitment which can be automatically or manually attached to the flexible-walled container or bag for dispensing flowable material contained within the bag. The enfitment, which extends through a wall of the second container, includes a piercing member to puncture the wall of the first container to form an opening and a sealing mechanism to seal the opening of the first container around the enfitment. The enfitment further includes a hollow tube having inner and outer surfaces and first and second open ends with the piercing member being formed at one end of the hollow tube. The piercing member and sealing mechanism are configured to interact with the wall of the flexible-walled container to form an opening in the container through which the flowable material can pass through the hollow tube and to stretch the opening around the outer surface of the hollow tube. The piercing member has a sharpened tip to penetrate the wall of the flexible-walled container.
The piston is positionable within the second container above the first container to apply pressure to at least a wall of the first flexible-walled container so as to compress the first flexible-walled container between the piston and the enfitment. The enfitment extends through a wall of the second container opposite the wall of the first flexible-walled container adjacent to the piston. In an automated embodiment, a drive mechanism rotates the enfitment about a rotational axis generally normal to a wall of the second container. As the enfitment is rotated, the piercing member punctures the flexible wall of the first container and the sealing mechanism interacts with the first container to form a seal therewith.
The enfitment is shaped so that the bag can be easily removed from the enfitment. As the enfitment is rotated in a reverse direction, a recess in the sealing mechanism guides the bag opening upward relative to the enfitment to unseal the flexible container from the enfitment. In an automated embodiment, the drive mechanism is simply reversed to unwind the enfitment from the flexible bag. Thus, the enfitment can be automatically attached to and detached from the bag by rotating the enfitment in an opposite rotational directions.
In a preferred embodiment, a piston includes a recess shaped to receive the portion of the enfitment which protrudes into the first container. For instance, a circular-shaped recess in a piston can receive a generally circular-shaped piercing member and sealing mechanism of the enfitment. Thus, as the piston reaches the end of its overall predetermined stroke length, a portion of the enfitment is received within the recess portion of the piston. In this manner, the amount of material dispensed from the bag can be maximized.
For dispensation of a controlled amount of flowable material from the flexible-walled container, the piston is actuated through a series of sequential dispensation steps. During each dispensation step, the piston is moved by a predetermined stroke length toward the first container to dispense a desired amount of material from the first container. A controlled displacement motor can be used to move the piston through the series of sequential dispensation steps.
Because the flexible-walled container can have an uneven shape, the predetermined stroke length of the piston for each dispensation step within the series of sequential dispensation steps can differ between at least two of the dispensation steps to achieve controlled dispensation of a predetermined amount of flowable material. As the bag sits within the second container or ingredient hopper, the top surface of the bag does not necessarily mirror the shape of the hopper. Toward the middle and bottom of the bag, the cross-sectional shape of the bag tends to be the same as the cross-sectional shape of the second container. Thus, if the piston travel for each dispensation step is constant, the amount of food product dispensed on the first few dispensations will be smaller than the amount of product later dispensed as the shape of the bag fills the entire shape of the second container.
The present invention provides a method for dispensing a controlled amount of flowable material from the flexible-walled container which includes determining the quantity of flowable material in the flexible-walled container, ascertaining the amount of piston travel for compressing the flexible-walled container within the second container which is required to dispense a desired amount of material from the flexible-walled container based on the determined quantity of flowable material in the flexible-walled container, and controlling the displacement of the piston to move the piston by the ascertained distance to dispense a predetermined amount of the material.
During the first dispensation step of the series of sequential dispensation steps, the piston can be moved by a stroke which is longer than the stroke length associated with a median dispensation step of the series of sequential dispensation steps. In this manner, generally the same amount of material which is dispensed at the first dispensation is also dispensed at the median dispensation.
Depending on the type of material to be dispensed, piston velocity can be also controlled in order to control product flow rate. In addition, in a preferred embodiment of the present invention, after dispensation associated with each sequential dispensation step of moving the piston toward the first container, the piston is moved by reverse travel away from the first container to reduce the pressure of the flowable material within the first container. Since continuing pressure on the first container can cause undesirable dripping of the flowable material, this back-up feature reduces dripping from an exit nozzle coupled to the first container through which the flowable material is dispensed. A pressure-release valve disposed within the exit nozzle can be used to control flow of the material from the first container so that material is dispensed as pressure is applied to the first container by the piston, yet when the pressure is reduced dripping from the nozzle is reduced or eliminated.
A method for dispensing controlled amounts of flowable material stored in a first flexible-walled container involves providing a base, positioning the first flexible-walled container in a second container being supported by the base, mounting a hollow enfitment through at least one wall of the second container for opening the first flexible-walled container and dispensing the flowable material therethrough, rotating a piston positionable within the second container to apply force to at least one wall of the first flexible-walled container so as to compress the first flexible-walled container between the piston and the enfitment, and driving the piston toward the base along a stroke axis to compress the first flexible-walled container against the second container to dispense the flowable material through the enfitment.